JSFiddle - React, Tailwind, and code Playground

HTML

<div id="dialog"><p>some body text</p></div>

JavaScript

$("#dialog").dialog( {zIndex: 50} );

function setzIndex() {
    $("#dialog").dialog("option", "zIndex", 100);
    alert($("#dialog").dialog("option", "zIndex"));
}

setTimeout(setzIndex, 2000, this);